General geology and potential limestone sinkhole by using Electrical Resistivity Imaging(ERI) at Gua Musang, Gua Batu Boh and Gua Serai in Kelantan

This research investigates whether there is a potential limestone karst that could form a sinkhole in Gua Musang, specifically, in Gua Musang, Gua Serai and Gua Batu Boh. The main objectives of the research were to 1) to produce the geological map of study area to 1:25,000 scale, 2) to investigate in the study area for potential geohazards near the limestone hills, 3) to clarify the depth of the limestone bedrock in the study area of Gua Musang. The research applies a geophysics method. A total of seven profile line that is used in order to covered the focussed study area. A geological mapping, geophysics, geographic information system (GIS), structural analysis and petrography analysis is used to gather data for this research. The study area conducted for geological mapping is 5 km distance in length and there are four types of lithology distributed in the study area, such as, Igneous rock (Granite), Sedimentary rock Limestone, Shale, and Sandstone) and Metamorphic rock (Marble, Schist and Phyllite). Stratigraphy for the study area begins with the oldest lithology formed, phyllite and limestone during Pennian, than, sandstone and shale during Triassic and lastly, granite the probably intrude into the surface during Tertiary. Then, a structural analysis conducted at four limestone hills, Gua Musang (Gua Mok), Gua Musang (Abandon Train Station), Gua Serai (Siamese Temple) and Gua Batu Boh (Indian Temple), each of the limestone hills had been effected by dissolution process and weathering process and in the structural analysis it indicate that the stability of each limestone had been compromise. In the petrography analysis indicate that there is certain part of the lithology in the study area had made contact or affected by contact metamorphism process due to faulting and intrusion of granite. The findings revealed that certain location from the three focussed limestone hills has the potential limestone karst that could form a sinkhole, the survey line shown potential risk is in GM 1, GM 2, GBB 2 and GBB 3, but, for GS 1, GS 2 and GBB 1 there is still potential for sinkholes formation because the foundation of the area is limestone and marble rock. These findings have a direct implications on the safety and insecurity of Gua Musang area. It proves that the geophysics method are able to discovered cavity in the sub-surface and able to interpret the data that could help locals civilian for their safety and awareness.